Device for Treating Glaucoma

ABSTRACT

An aqueous humor drainage device for implantation into a tissue passage leading into the anterior chamber of the eye. In one aspect, the device includes a flexible tube and a tissue sealing structure extending radially outward from the tube in at least two different directions. The tissue sealing structure is spaced apart from and intermediate cylindrical outer surfaces of proximal and distal portions of the tube. The tissue sealing structure extends radially outward beyond the cylindrical outer surfaces of the proximal and distal portions of the tube. The tissue sealing structure has a second maximal cross-sectional dimension that is greater than a first maximal cross-sectional dimension of the tube and is configured to interface to the tissue passage and form a seal between the tissue passage and the tissue sealing structure. Other aspects are also described and claimed.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation of U.S. application Ser. No.14/815,084, filed on Jul. 31, 2015, which is a continuation of U.S.application Ser. No. 13/348,931, filed Jan. 12, 2012, now U.S. Pat. No.9,101,444, which are hereby incorporated by reference herein in theirentireties.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to surgical treatment of glaucoma. Moreparticularly, this invention relates to medical devices and materialsfor diverting aqueous humor out of the anterior chamber through asurgically implanted duct passageway.

2. State of the Art

Glaucoma is a progressive ocular disease that manifests itself throughelevated intraocular pressure (“IOP”). High pressure develops in an eyebecause of impaired outflow of aqueous humor. In open-angle glaucoma,the impaired outflow is caused by abnormalities of the drainage systemof the anterior chamber. In closed-angle glaucoma, the impaired outflowis caused by impaired access of aqueous to the drainage system. If thepressure within the eye remains sufficiently high for a long enoughperiod of time, total vision loss occurs. Thus, glaucoma is a leadingcause of preventable blindness.

As shown in FIG. 1, the eye 10 is a hollow structure wherein theanterior chamber 20 contains a clear fluid called aqueous humor. Aqueoushumor is formed by the ciliary body 12 adjacent the posterior chamber 9of the eye. The fluid, which is made at a fairly constant rate, thenpasses around the lens 14, through the pupillary opening in the iris 18and into the anterior chamber 20. Once in the anterior chamber 20, thefluid drains out of the eye 10 through two different routes. In theuveoscleral route, the fluid percolates between muscle fibers of theciliary body 12. This route accounts for approximately ten percent ofthe aqueous outflow in humans. The primary pathway for aqueous outflowin humans is through the canalicular route, which involves thetrabecular meshwork (not shown) and Schlemm's canal 24.

The trabecular meshwork and Schlemm's canal 24 are located at thejunction between the iris 18 and the sclera 26. This junction, which istypically referred to as the angle, is labeled 28. The trabecularmeshwork is a wedge-shaped structure that runs around the circumferenceof the eye. It is composed of collagen beams arranged in athree-dimensional sieve-like structure. The beams are lined with amonolayer of cells called trabecular cells. The spaces between thecollagen beams are filled with an extracellular substance that isproduced by the trabecular cells. These cells also produce enzymes thatdegrade the extracellular material. Schlemm's canal 24 is disposedadjacent to the trabecular meshwork. The outer wall of the trabecularmeshwork coincides with the inner wall of Schlemm's canal 24. Schlemm'scanal 24 is a tube-like structure that runs around the circumference ofthe cornea. In human adults, Schlemm's canal is believed to be dividedby septa into a series of autonomous, dead-end canals. The aqueous fluidtravels through the spaces between the trabecular beams of thetrabecular meshwork, across the inner wall of Schlemm's canal 24 intothe canal, through a series of collecting channels that drain fromSchlemm's canal 24 and into the episcleral venous system (not shown).

The tough outer membrane known as the sclera 26 covers all of the eye 10except that portion covered by the cornea 34, which is the thin,transparent membrane which covers the pupillary opening and the iris 18.The cornea 34 merges into the sclera 26 at a juncture referred to as thelimbus 32. A portion of the sclera 26 is covered by a thin tissue calledTenon's membrane 36 (also called Tenon's capsule), which envelopes thebulb of the eye from the optic nerve (not shown) to the ciliary region.Near its front, Tenon's membrane 36 blends into the conjunctiva 30 whereit is attached to the ciliary region of the eye as shown.

In a normal patient, aqueous humor production is equal to aqueous humoroutflow and intraocular pressure remains fairly constant (typically inthe 8 to 18 mmHg range). In glaucoma, there is abnormal resistance toaqueous humor outflow, which manifests itself as increased IOP.Tonometry is the measurement of IOP. In primary open angle glaucoma,which is the most common form of glaucoma, the abnormal resistance isbelieved to be along the outer aspect of trabecular meshwork and theinner wall of Schlemm's canal 24. Primary open angle glaucoma accountsfor approximately eighty-five percent of all glaucoma. Other forms ofglaucoma (such as angle closure glaucoma and secondary glaucomas) alsoinvolve decreased aqueous humor outflow through the canalicular pathwaybut the increased resistance is from other causes such as mechanicalblockage, inflammatory debris, cellular blockage, etc.

With the increased resistance, the aqueous humor builds up because itcannot exit fast enough. As the aqueous humor builds up, the IOP withinthe eye increases. The increased IOP compresses the axons in the opticnerve and also may compromise the vascular supply to the optic nerve.The optic nerve carries vision from the eye to the brain. Some eyes seemmore susceptible to damage from excessive IOP than other eyes. Whileresearch is investigating ways to protect the nerve from an elevatedpressure, the therapeutic approach currently available in glaucoma is toreduce the intraocular pressure.

The clinical treatment of glaucoma is typically carried out in astep-wise manner. Medication often is the first treatment option.Administered either topically or orally, these medications work toeither reduce aqueous production or they act to increase outflow. If onemedication fails, the patient is oftentimes given a second medicationand then a third and fourth. It is not unusual to have glaucoma patientson four separate medications. Currently available medications have manyserious side effects including: congestive heart failure, respiratorydistress, hypertension, depression, renal stones, aplastic anemia,sexual dysfunction and death. In addition, the preservatives in variousmedications are known to cause damage to the endothelial cellsunderlying the cornea which can manifest as opacification of the cornea.Further, the preservatives can also change the characteristics of theconjunctiva which can lead to additional filtration problems. Compliancewith medication is also a major problem, with estimates that over halfof glaucoma patients do not follow their correct dosing schedules whichcan lead to progressive vision loss.

When medication fails to adequately reduce the IOP, lasertrabeculoplasty is often performed. In laser trabeculoplasty, thermalenergy from a laser is applied to a number of noncontiguous spots in thetrabecular meshwork. It is believed that the laser energy stimulates themetabolism of the trabecular cells in some way, and changes the cellularmaterial in the trabecular meshwork. In a large percent of patients,aqueous humor outflow is enhanced and IOP decreases. However, the effectoften does not last long and a significant percentage of patientsdevelop an elevated IOP within the years that follow the treatment. Thelaser trabeculoplasty treatment is typically not repeatable. Inaddition, laser trabeculoplasty is not an effective treatment forprimary open angle glaucoma in patients less than fifty years of age,nor is it effective for angle closure glaucoma and many secondaryglaucomas.

If laser trabeculoplasty does not reduce the IOP sufficiently, thenincisional surgery (typically referred to as filtering surgery) isperformed. The most commonly performed incisional procedure istrabeculectomy. The trabeculectomy procedure involves cutting a“trapdoor” in the sclera and then from within the wall of the trapdoor,punching a hole into the anterior chamber which allows fluid to drainfrom the anterior chamber into the trapdoor, out the “door” of thetrapdoor and then into a bleb (a blister-like formation) under theconjunctiva, thereby decreasing IOP. Sutures are placed under controlledtension to keep the door of the trapdoor sufficiently closed in order tocontrol IOP and avoid hypotony (i.e., low IOP). This procedure isrelatively difficult to perform correctly and has a high level oflong-term complications. Additional interventions often need to beperformed to adjust the tension in the sutures to further control IOP.

When trabeculectomy doesn't successfully lower the eye pressure, thenext step, and usually the last, is a surgical procedure that implants aglaucoma drainage implant (GDI) that shunts aqueous humor from theanterior chamber to control the IOP. One such GDI, as shown in U.S. Pat.No. 6,050,970 to Baerveldt, is a drainage tube that is attached at oneend to a plastic plate. The drainage tube is comprised of a siliconerubber shunt with an outer diameter of between 1.0 and 3.0 French;preferably with an inner diameter of 0.3 mm and an outer diameter of 0.6mm (1.8 French). The Baerveldt tube is implanted by first making anincision in the conjunctiva 30, exposing the sclera 26 and the naturalplane between the sclera and conjunctiva/Tenon's membrane is dissecteddown to slightly beyond the equator. The plastic plate is sewn to thesurface of the sclera posteriorly, usually over the equator. A fullthickness hole is made into the eye under the limbus 32, usually with aneedle. The tube is inserted into the eye through this needle tract. Theexternal portion of the tube is covered with either cadaver sclera orother equivalent tissue to prevent it from eroding through theconjunctiva. The conjunctiva 30 is replaced and the incision is closedtightly. With this shunt device, aqueous drains out of the anteriorchamber through the tube and along the surface of the plate and into thebleb, where the bleb is defined as a thin layer of connective tissuethat encapsulates the plate and tube. The plate typically has a largesurface area, which can be as large as 20 mm in diameter, in order towick and disperse fluid. Once fluid accumulates in the bleb, it canabsorb through the tissues of the bleb and into the venous system of thesclera or to the surface of the eye where it can evaporate or collect inthe tear ducts. These plates are generally made of silicone rubber,which eventually becomes encapsulated by the connective tissue of thebleb. These large encapsulated plates are irritating to some patients.

Some of the current approved GDIs include valving of the tube thatenters the anterior chamber of the eye in order to control IOP and avoidhypotony. In addition, many GDI's including the aforementioned Baerveldtvalve have their tubes tied off to prevent hypotony in the acute phasebefore capsules form around the device. The ligating sutures are thencleaved with a laser or dissolve within a month.

Current GDIs have an effective half life of two to five years fromimplantation before a second, third or fourth GDI is required. Due tothe bulky size of current GDIs, there is room for only three devices inthe eye; rarely is a fourth device implanted. The problems associatedwith current generation GDIs are:

Impairment of eye motion and resulting double vision (diplopia).

Hypotony (low IOP which could result in a detached retina).

Erosion of conjunctiva and infection and associated high costs of usinga cadaver sclera to prevent erosion. Furthermore, cadaver sclera isdifficult to obtain outside the U.S. and several religions do not permitthe use of cadaver tissue in the body.

Severe encapsulation of the plate which prevents proper filtering offluid and leads to poor IOP control.

The difficulty of performing trabeculectomies and GDI's as well as theirassociated morbidities led to development of a novel glaucoma drainageimplant described in U.S. Pat. Nos. 7,431,709; 7,594,899; and 7,837,644;commonly assigned to assignee of the present invention and hereinincorporated by reference in their entireties.

SUMMARY OF THE INVENTION

In embodiments, an aqueous humor drainage device is provided forimplantation into a tissue passage leading into the anterior chamber ofthe eye. The device includes a flexible tube and a tissue sealingstructure extending radially outward from the tube in at least twodifferent directions. The tissue sealing structure is spaced apart fromand intermediate cylindrical outer surfaces of proximal and distalportions of the tube. The tissue sealing structure extends radiallyoutward beyond the cylindrical outer surfaces of the proximal and distalportions of the tube. The tissue sealing structure has a second maximalcross-sectional dimension that is greater than a first maximalcross-sectional dimension of the tube and is configured to interface tothe tissue passage and form a seal between the tissue passage and thetissue sealing structure. The seal surrounds the entire circumferentialperimeter of the device and seal prevents leakage of aqueous humorthrough the space between the tube and the surrounding ocular tissue.The tissue sealing structure can also act to fix the device in place inthe tissue passage and minimize migration of the device in both theproximal and distal directions. The maximum cross-sectional diameter ofthe tissue sealing structure can be defined by at least one bluntsurface (with only rounded features) to facilitate sealing.

In one embodiment, the tissue sealing structure is realized by two tabsthat are disposed opposite one another on opposite sides of the tube.The two tabs can be generally planar in form and lie in a common planethat extends transverse to the central axis of the tube. The generallyco-planar configuration of the tabs minimizes the profile of the devicein order to reduce erosion and migration of the device. The two tabs canbe mirror images of one another reflected about the central axis of thetube. The outer edges of the tabs can have a tapered profile facing thedistal end of the tube. This tapered profile facilitates introduction ofthe tabs into the passage formed by the needle body. The tabs can have aprofile that tapers in the radial direction (i.e., the direction of thecommon plane of the two tabs) transverse to the central axis of thetube.

In one embodiment, the instruments of the kit (including at least onehand-held instrument and at least one aqueous humor drainage device) arehoused in one or more enclosures that provide the surgeon easy access tothe instruments as needed. The enclosure(s) can be realized fromsuitable material (such as a thermoplastic) that is inexpensive andreadily disposable for one-time use. Other materials (such as stainlesssteel and the like) suitable for non-disposable applications can also beused.

An inserter can be used to deploy the device into the passage leading tothe anterior chamber of the eye. The inserter can be realized by anapparatus similar to that described in U.S. Pat. Nos. 7,431,7091;7,594,899; and 7,837,644 with one or two slots that accommodate the tabsof the device. Alternatively, the inserter can be realized by a styletand/or a trocar device as described below. In such embodiments, theinserter can be part of the instrument kit housed in the enclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustration showing anatomic details of the human eye.

FIG. 2 is a schematic view of an embodiment of a hand-held instrumentfor defining a surgical passage through tissue leading into the anteriorchamber of the eye.

FIG. 3 is a perspective view of an embodiment of an aqueous humordrainage device that drains aqueous humor from the anterior chamber ofthe eye.

FIG. 4 is a perspective view of an embodiment of a surgical kitenclosure.

FIG. 5 is a side view of an illustrative embodiment of a needle bodythat is part of the hand-held instrument of FIG. 2.

FIG. 6 is a top view of an illustrative embodiment of the aqueous humordrainage device of FIG. 3.

FIG. 7 is a side view of an illustrative embodiment of the aqueous humordrainage device of FIG. 3.

FIGS. 8-11 are perspective views of different embodiments of an aqueoushumor drainage device.

FIGS. 12A-12D are cross-sectional schematic views of views of differentembodiments of an aqueous humor drainage device, showing the maximumdimension cross-sectional profiles of the sealing tabs of the respectiveembodiments.

FIG. 13A is a top view of an embodiment of an aqueous humor drainagedevice.

FIG. 13B is a cross-sectional schematic view of the aqueous humordrainage device of FIG. 13A through the cross-section labeled 13B-13B,showing a circular cross-sectional profile of the sealing tabs of theaqueous humor drainage device.

FIG. 14A is a top view of an embodiment of an aqueous humor drainagedevice.

FIG. 14B is a cross-sectional schematic view of the aqueous humordrainage device of FIG. 14A through the cross-section labeled 14B-14B,showing an oblong cross-sectional profile defined by the sealing tabs ofthe aqueous humor drainage device.

FIG. 15 is an illustration showing the aqueous humor drainage device ofFIG. 3 implanted into the eye to shunt aqueous humor from the anteriorchamber to a space between Tenon's membrane and the sclera of the eye.

FIG. 16 is a schematic view illustrating an embodiment of a stylet andan aqueous humor drainage device, the stylet for use in positioning theaqueous humor drainage device.

FIG. 17 is a schematic view illustrating another embodiment of a styletand an aqueous humor drainage device, the stylet for use in positioningthe aqueous humor drainage device.

FIG. 18A is a schematic illustration of an embodiment of a knife used ina surgical method for treating elevated intraocular pressure, the knifefor defining a passage through tissue and in communication with theanterior chamber of the eye.

FIG. 18B is a magnified view of the distal end of the knife of FIG. 18A.

FIG. 18C is a schematic illustration of an embodiment of a hand-heldinstrument used in a surgical method for treating elevated intraocularpressure, the instrument for defining a passage through tissue and incommunication with the anterior chamber of the eye.

FIG. 19 is a side view of an embodiment of a trocar device used in asurgical method for treating elevated intraocular pressure, the trocardevice inserted into a passage through tissue and in communication withthe anterior chamber of the eye, and the trocar device receiving thetube of an aqueous humor drainage device for insertion of the tube ofthe aqueous humor drainage device into the passage.

FIGS. 20A to 20E illustrate the function of the trocar device of FIG. 19in an exemplary surgical method.

FIG. 21 is a side view of an alternate embodiment of a trocar deviceused in a surgical method for treating elevated intraocular pressure,the trocar device inserted into a passage through tissue and incommunication with the anterior chamber of the eye, and the trocardevice receiving the tube of an aqueous humor drainage device forinsertion of the tube of the aqueous humor drainage device into thepassage.

FIGS. 22A to 22D illustrate the function of the trocar device of FIG. 21in an exemplary surgical method.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As used herein, the term “distal” is generally defined as in thedirection of the eye of the patient, or away from a user of thesystem/apparatus/device. Conversely, “proximal” generally means in thedirection away from the eye of the patient, or toward the user of thesystem/apparatus/device.

Turning now to FIGS. 2 and 3, there is shown an embodiment of a kit fortreating glaucoma, which includes at least one hand-held instrument 101(FIG. 2) and at least one aqueous humor drainage device 201 (FIG. 3).The instrument 101 has a needle body 103 that is inserted through oculartissue into the anterior chamber 20 of the eye (FIG. 1) to define apassage through the tissue leading into the anterior chamber 20. Theneedle body 103 has a maximal cross-sectional dimension (e.g., diameterD1 of FIG. 5) along its length. The proximal end of the needle body 103is rigidly coupled to a hub 105. A handle 107 is rigidly coupled to thehub 105. The handle 107 is gripped by the fingers of the surgeon formanipulation of the needle body 103 as desired. A needle cover 109 canextend over the needle body 103 for safety. The needle body 103 can havea hollow-bore (or possibly a solid bore). The hub 105 and the handle 107can be realized by a syringe body that includes a plunger that fitsinside a tube as is well known. A solution can be loaded into the tubeand pumped through the hollow-bore needle body 103 by hand manipulationof the plunger. In addition, the needle body may be bent into a moredesirable shape to precisely place the needle tract, especially when thepatient's nose is in the way of the needle handle.

The aqueous humor drainage device 201 includes a flexible tube 203 thatdefines a duct 205 for diverting aqueous humor from the anterior chamber20. The tube 203 has a proximal end 207 and distal end 209 opposite oneanother. The distal end 209 can have a tapered profile that facilitatesinsertion into the passage leading to the anterior chamber 20 formed bythe needle body 103. The tube's outer surface 211 has a maximalcross-sectional dimension (e.g., outer diameter D2 of FIG. 7) that isless than the maximal cross-sectional dimension of the needle body 103(e.g., diameter D1 of FIG. 5). The device 201 also includes first andsecond tabs or fins 213A, 213B that are spaced apart from the proximaland distal ends 207, 209 of the tube 203. The tabs 213A, 213B extendradially outward beyond the outer surface 211 of the tube 203 oppositeone another on opposing sides of the tube 203. The first and second tabs213A, 213B can be generally planar in form and lie in a common planethat extends transverse to the central axis of the tube 203 as bestshown in FIG. 3. The generally co-planar configuration of the tabs 213A,213B, when placed flat against the sclera of the eye, minimizes theprofile of the device in order to reduce erosion and migration. Thefirst and second tabs 213A, 213B can be mirror images of one anotherreflected about the central axis of the tube 203 as shown. Tab 213Adefines an outer edge 215A, and tab 213B defines an outer edge 215B. Themaximal distance between the outer edge 215A and the outer edge 215Bdefine a maximal cross-sectional dimension that is greater that themaximal cross-sectional dimension of the needle body 103 (e.g., outerdiameter D1 of FIG. 5). The tabs 213A, 213B are operably disposed withinthe passage defined by the needle body 103 and their dimensions causethe surrounding tissue to directly contact the tabs 213A, 213B in orderto form a seal between the surrounding tissue and the tabs 213A, 213B.The seal surrounds the entire circumferential perimeter of the devicedefined by the tabs 213A, 213B and prevents leakage of aqueous humorthrough the space between the tube 203 and the surrounding tissue. Theneedle-defined passage can also be widened in the scleral area with theuse of a sharp knife and associated stab wound. The widened part can beformed either before or after formation of the needle-defined passage.The tabs 213A, 213B can deform in the passage as they are inserted intothe passage in response to forces applied by the surrounding tissue,and/or the surrounding tissue can deform (bycompressing/stretching/thinning) as the tabs 213A, 213B are insertedinto the passage. Such deformation is controlled by the maximalcross-sectional dimension of the tabs 213A, 213B relative to thecross-sectional dimension of the passage (as formed by the needle body103 or stab wound) as well as the hardness of the material of the tabs213A, 213B. The tabs 213A, 213B also act to fix the device 201 in placein the passage and minimize migration of the device 201 in both theproximal and distal directions.

The outer edges 215A, 215B of the tabs 213A, 213B can have a taperedprofile facing the distal end 209 as best shown on FIG. 3. This taperedprofile facilitates introduction of the tabs 213A, 213B into the passageformed by the needle body 103.

The tabs 213A, 213B can have respective profiles that taper in theradial direction (i.e., the direction of the common plane of the tabs)transverse to and away from the central axis of the tube 203 as bestshown in FIG. 3.

The outer surface 211 of the tube 203 has a maximal cross-sectionaldimension (e.g., outer diameter D2) that is less than the maximalcross-sectional dimension of the needle body 103. For example, the outersurface 211 can have an outer diameter D2 less than 0.4 mm (such as onthe order of 0.35 mm) for a needle body 103 with a maximalcross-sectional dimension of 0.4 mm. In one embodiment, the duct 205 ofthe tube 203 is a simple constant-diameter lumen with a diameter in therange between 0.05 mm and 0.15 mm. This small duct diameter limitsaqueous humor flow through the tube 203 and provides for control overTOP without the need for unidirectional valves or other structures (suchas filters) that limit aqueous humor flow through the tube. Morespecifically, the diameter of the duct 205 alone controls the flow rateof aqueous humor through the duct 205 and thus controls the TOP of thepatient. The appropriate duct diameter can vary among patients dependingon the production rate of aqueous humor and the extent of clogging ofthe natural drainage paths of the patient and thus can be selected bythe physician as desired.

In one embodiment, the instruments of a kit, including at least onehand-held instrument 101 (FIG. 2) and at least one aqueous humordrainage device 201 (FIG. 3) as described herein, are housed in one ormore enclosures, such as an instrument tray 401 as shown in FIG. 4, thatprovides the surgeon easy access to the instruments as needed. Theinstrument tray 401 can be realized from suitable material (such as athermoplastic) that is inexpensive and readily disposable for one-timeuse. Other materials (such as stainless steel and the like) suitable fornon-disposable applications can also be used. The kit can include aplurality of hand-held instruments 101 (FIG. 2) with needle bodies ofdifferent diameters and/or a plurality of aqueous humor drainage devices201 (FIG. 3) with tube ducts and/or tabs of different sizes (forexample, a plurality of devices 201 with different tab sizes thatcorrespond to varying needle body diameters of the instruments 101 ofthe kit). In addition, to affect the stab incision, knives of differentdiameters (discussed hereinafter with respect to FIGS. 18A and 18B) canbe included in the kit as well as measuring devices, medications,sponges to apply medication, measuring devices, markers, syringes,rinsing fluid, trocars, inserters and the like.

An inserter can be used to deploy the device 201 into the passageleading to the anterior chamber 20 formed by the needle body 103. Theinserter can be realized by an apparatus similar to that described inU.S. Pat. Nos. 7,431,709, 7,594,899, and 7,837,644 with one or two slotsthat accommodate the tabs 213A, 213B of the device 201. Alternatively,the inserter can be realized by a stylet and/or a trocar device asdescribed below. In such embodiments, the inserter can be part of theinstrument kit housed in the tray 401.

FIG. 5 shows the dimensions of an exemplary embodiment of the needlebody 103. In this exemplary embodiment, the needle body 103 has an outerdiameter D1 of 0.4 mm (i.e., 27 gauge). Other suitable outer diametersD1 can be in the range from 0.4 mm (i.e., 27 gauge) to 0.635 mm (i.e.,23 gauge). The needle body 103 can also be provided bent into adesirable shape to allow the needle to be inserted into the eye at anangle that, if not bent, would interfere with the patient's nose.

FIGS. 6 and 7 shows the dimensions of an exemplary embodiment of anaqueous humor drainage device 201 for use with the needle body 103 ofFIG. 5. The tube 203 has a length of 8.5 mm. The duct 205 has a diameterof 0.07 mm. The outer surface 211 has a maximal cross-sectional diameter(diameter D2) of 0.35 mm, which is less than the outer diameter D1 ofthe needle body 103. The tabs 213A, 213B are spaced by 4.5 mm from thedistal end 209 of the tube 203 and spaced by 3 mm from the proximal end207 of the tube 203. The tabs 213A, 213B are generally planar in formand lie in a common plane that extends transverse to the central axis ofthe tube 203. The tabs 213A, 213B are mirror images of one anotherreflected about the central axis of the tube 203 as shown. The planarform of the first and second tabs 213A, 213B has a maximal thickness onthe order of 0.35 mm (i.e., the outer diameter D2 of the tube 203), alengthwise dimension of 1 mm parallel to the central axis of the tube203, and a maximal cross-sectional dimension between the edges 215A,215B of 1.1 mm. In other designs, the maximal cross-sectional dimensionbetween the edges 215A, 215B can be in the range between 0.9 mm and 1.5mm. Such maximal cross-sectional dimension is significantly larger thanthe outer diameter D1 of 0.4 mm for the needle body 103 of FIG. 5.

FIGS. 8 to 14B illustrate alternate designs for the tabs of theimplantable aqueous humor drainage device. In the design of FIG. 8, thetabs 213A1, 213B1 have a profile that tapers in the radial directiontransverse to the central axis of the tube 203 where the tapered radialsurfaces of the tabs extend from a flat feature 217. In the design ofFIG. 9, the tabs 213A2, 213B2 are parts of a triangular wedged-shapedbody 219 disposed along the lengthwise extent of the tube 203. Theproximal walls 221A, 221B of the wedge-shaped body 219 are orientedtransverse to the central axis of the tube 203, which is intended to aidin reducing migration of the tube 203 in the proximal direction out ofthe passage formed by the instrument 101. In the design of FIG. 10, thetabs 213A3, 213B3 have proximal walls 223A, 223B that are orientedtransverse to the central axis of the tube 203, which is intended to aidin reducing migration of the tube 203 in the proximal direction out ofthe passage formed by the instrument 101. In the design of FIG. 11, thetabs 213A4, 213B4 each have a curved wedge-shaped form. In the design ofFIG. 12A, the tabs 213A5, 213B5 and tube 203 define a cross-sectionalprofile of rhombus with radiused corners (in particular, the rhombusprofile tapers in the radial direction transverse to and away from thecentral axis of the tube 203). The tapered surfaces of the tabs 213A5,213B5 extend from the annular surface of the tube 203 as shown. In thedesign of FIG. 12B, the tabs 213A6, 213B6 define a cross-sectionalprofile of an oblong with semicircular ends as shown. Alternatively, thetabs 213A6, 213B6 can define a cross-sectional profile of an oblong withsemielliptical ends. In the design of FIG. 12C, the tabs 213A7, 213B7define a cross-sectional profile of an ellipse whose boundary is offsetradially from and surrounds the annular surface of the tube 203. In thedesign of FIG. 12D, the tabs 213A8, 213B8 define a cross-sectionalprofile of a larger radius ellipse (as compared to the ellipticalprofile of FIG. 12C) whose boundary is offset radially from andsurrounds the annular surface of the tube 203.

In the design of FIGS. 13A and 13B, a cork-like tab 213′ is providedthat extends circumferentially beyond the annular surface of the tube203. The cork-like tab 213′ has a cross-sectional profile of a circle asis evident from the view of FIG. 13B.

In the design of FIGS. 14A and 14B, a generally planar tab 213″ isprovided that extends circumferentially beyond the annular surface ofthe tube 203. The generally planar tab 213″ has a cross-sectional oblongprofile as is evident from the view of FIG. 14B.

The outer surface(s) of the tab(s) of the device 201 can be blunt withrounded features as shown, and thus avoid any sharp corners and edges.The blunt outer surface(s) of the tab(s) is particularly suited toforming a seal to the surrounding tissue as described herein.

In the design of FIG. 11, a slit 225 is formed in the tabs 213A, 213B ina manner such that the slit 225 transects the lumen 205 of the aqueoushumor drainage device 205. The slit 225 is positioned proximal to thatpart of the tabs 213A, 213B that forms the seal to the surroundingtissue (i.e., the blunt exterior edges of the tabs 213A, 213B at theirmaximal radial distance with respect to the central axis of the tube203). The purpose of the slit 225 is two-fold. First, the slit 225 canact as a pressure relief valve in the event the lumen 205 of the aqueoushumor drainage device 205 becomes clogged downstream due to overgrowthof tissue in the bleb. The elastomeric nature of the aqueous humordrainage device 205 is such that as pressure builds up within the lumen205, the slit 225 can deform into an open state where aqueous humor isreleased into the bleb thereby reducing pressure in the anteriorchamber. The second advantage of the slit 225 is to deliberatelyaccomplish the same purpose; that is to relieve pressure in the anteriorchamber. In order to effectuate this release, the lumen 205 downstreamfrom the slit 225 is sealed closed thereby forcing fluid to escapethrough the slit 225. The length and width of the slit 225 controls thepressure at which aqueous humor escapes and can be tailored to preventhypotony. The aqueous humor escapes through the slit 225 and flowsproximally in the space between the surrounding tissue and the outersurface of the proximal part of the tube 203. Fluid that escapes throughthe slit 225 will have its pressure dropped by both the narrow lumen 205of the distal part of tube 203 as well as the slit 225. Periannularleakage of aqueous humor in the space between the surrounding tissue andthe outer surface of the distal part of the tube 203 is blocked by theseal formed by the tabs 213A, 213B. More specifically, the bluntexterior edges of the tabs 213A, 213B at their maximal radial offsetwith respect to the central axis of the tube 203 forms a seal with thesurrounding tissue that blocks such periannular leakage of aqueoushumors.

The aqueous humor drainage device 201 can be formed of a homogenouspolymeric material. In one embodiment, the homogenous polymeric materialis a polyolefinic copolymer material having a triblock polymer backbonecomprising polystyrene-polyisobutylene-polystyrene, which is hereinreferred to as “SIBS”. SIBS can also be referred to aspoly(styrene-b-isobutylene-b-styrene) where b stands for “block”. Highmolecular weight polyisobutylene (PIB) is a soft elastomeric materialwith a Shore hardness of approximately 10A to 30A. When copolymerizedwith polystyrene, it can be made at hardnesses ranging up to thehardness of polystyrene, which has a Shore hardness of 100D. Thus,depending on the relative amounts of styrene and isobutylene, the SIBSmaterial can have a range of hardnesses from as soft as Shore 10A to ashard as Shore 100D. In this manner, the SIBS material can be adapted tohave the desired elastomeric and hardness qualities. In the preferredembodiment, the SIBS material of the aqueous humor drainage device tube201 has a hardness less than Shore 50A and greater than Shore 20A.Details of the SIBS material is set forth in U.S. Pat. Nos. 5,741,331;6,102,939; 6,197,240; 6,545,097, which are hereby incorporated byreference in their entirety. The SIBS material of the aqueous humordrainage device 201 may be polymerized under control means usingcarbocationic polymerization techniques such as those described in U.S.Pat. Nos. 4,276,394; 4,316,973; 4,342,849; 4,910,321; 4,929,683;4,946,899; 5,066,730; 5,122,572; and Re 34,640, each herein incorporatedby reference in its entirety. The amount of styrene in the copolymermaterial is preferably between 16 mole % and 30 mole % and mostpreferably between 20 mole % and 27 mole %. The styrene and isobutylenecopolymer materials are preferably copolymerized in solvents.

Alternative glassy segments to the aforementioned styrene can be used torealize the aqueous humor drainage device 201. The glassy segmentprovides a hardener component for the elastomeric polyisobutylene. Theglassy segment preferably does not contain any cleavable group whichwill release in the presence of body fluid inside the human eye andcause toxic side effects and cell encapsulation. The glassy segment canbe a vinyl aromatic polymer (such as styrene, α-methylstyrene, or amixture thereof), or a methacrylate polymer (such as methylmethacrylate,ethylmethacrylate, hydroxymethalcrylate, or a mixture thereof). Suchmaterials preferably have a general block structure with a centralelastomeric polyolefinic block and thermoplastic end blocks. Suchmaterials have a general structure:

-   -   BAB or ABA (linear triblock),    -   B(AB)n or a(BA)n (linear alternating block), or    -   X-(AB)n or X-(BA)n (includes diblock, triblock and other radial        block copolymers), where A is an elastomeric polyolefinic block,        B is a thermoplastic block, n is a positive whole number and X        is a starting seed molecule.        Such materials may be star-shaped block copolymers (where n=3 or        more) or multi-dendrite-shaped block copolymers. In addition to        the glassy segments, crosslinkers can be incorporated into the        polymer to provide a thermal-set version of SIBS. Exemplary        polymers incorporating these crosslinkers are described in        detail in U.S. Patent Publication 20090124773, herein        incorporated by reference in its entirety. These materials        collectively belong to the polymeric material referred to herein        as SIBS material.

Other polymeric materials can be used to provide aqueous drainage device201 according to this invention. Exemplary materials are flexiblematerials that can conform to the surface of the eye and include but arenot limited to silicone rubber, polyolefins (butyl rubber,polybutadiene, styrene-ethylene-propylene-butadiene, polyethylene,polypropylene, etc.) polyurethane (polyether urethanes, polycarbonateurethanes, polyurethanes containing polyisobutylene or other polyolefinsoft segments, etc.); acrylics (polyacrylates,poly(2-hydroxyethylmethacrylate), etc.), fluoropolymers (PTFE, ePTFE,fluorosilicones, poly(—CH2-CF2)-, etc.), polyamides, hydrogels,biological based structures such as those comprised of collagen,elastin, etc.; and blends of all the above materials as well as softfoams and porous polymer materials can be used to realize the aqueoushumor drainage device 201. The polymeric material should bebiocompatible and biostable within the ocular environment.

The entire aqueous humor drainage device 201 can be formed as a unitarypart by molding the polymeric material. It is also contemplated that thepolymeric material of the tabs 213A, 213B can be different from thepolymeric material of the tube 203. This can be accomplished by insertmolding techniques or other suitable thermoplastic forming techniques.The hardnesses of the tabs 213A, 213B can be the same as the tube 203,or they can differ from the tube 203. In one embodiment, the hardnessesof the tabs 213A, 213B are within the range between Shore 30A and Shore80A.

Turning now to FIG. 15, there is shown the aqueous humor drainage device201 implanted such that its distal end 209 is positioned within theanterior chamber 20 of the eye and its proximal end 207 is positioned ina pouch 300 formed between Tenon's membrane 36 and the sclera 26 (FIG.1). The pouch 300 defines a closed space between Tenon's membrane 36 andthe sclera 26 (FIG. 1). The duct 205 of the aqueous humor drainagedevice 201 shunts aqueous humor from the anterior chamber 20 to thepouch 300, which forms a shallow bleb. Aqueous humor is absorbed intothe adjacent tissue and ends up in the venous system in the eye or inthe tear film or simply evaporates from the outside of the conjunctivaonce it reaches such.

The pouch 300 can extend rearward from a location at or near the limbusto the posterior portion of the globe of the eye near or past theequator of the eye. The pouch 300 can be defined by making an incisionthrough the conjunctiva or Tenon's membrane 36 to the surface of thesclera and then dissecting and separating Tenon's membrane 36 from thesclera 26 (FIG. 1) over the area of the pouch 300. If the hinge from thepouch is in the fornix of the eye, this type of pouch is known as afornix-based pouch. If the hinge is at the limbus and the incision inthe fornix, this type of pouch is known as a limbus-based pouch. Thedistal end 209 of the aqueous humor drainage device 201 is insertedthrough a needle-formed passage through the angle 28 to the anteriorchamber 20 of the eye. The device 201 is advanced further into thepassage such that tabs 213A, 213B (only tab 213A is shown in FIG. 15)are positioned within the passage. The dimensions of the tabs 213A, 213Bcause the surrounding tissue to directly contact the tabs 213A, 213B inorder to form a seal between the surrounding tissue and the tabs 213A,213B. The seal surrounds the entire circumferential perimeter of thedevice defined by the tabs 2213A, 213B and prevents leakage of aqueoushumor through the space between the tube 203 and the surrounding tissue.The tabs 213A, 213B can deform in the passage as they are inserted intothe passage in response to forces applied by the surrounding tissue,and/or the surrounding tissue can deform (by stretching/thinning) as thetabs 213A, 213B are inserted into the passage. Such deformation iscontrolled by the maximal cross-sectional dimension of the tabs 213A,213B relative to the cross-sectional dimension of the passage (as formedby the needle body 103) as well as the hardness of the material of thetabs 213A, 213B. The tabs 213A, 213B also act to fix the tube 203 inplace in the passage and minimize migration of the tube 203 in both theproximal and distal directions. After proper positioning of the device201, the pouch 300 is closed. A sponge, blotting paper or other suitablecarrier loaded with an anti-proliferative agent can be placed within thepouch 300 before it is closed. The anti-proliferative agent may be, forexample, mitomycin C or 5-Fuorouracil or other antimetabolites or othersuitable drug(s) or compound(s) that releases immediately or over timeand functions to minimize fibrosis of the conjuctiva-sclera to Tenon'smembrane, thereby maintaining the structure of the pouch 300 over anextended period of time. Alternatively, a collagen sponge or otherspace-filler structure or fluid can be placed in the pouch to preventhealing of the conjunctiva/Tenon's membrane to the sclera. Aqueous humorflows from the anterior chamber 20 through the duct 205 of the device203 and into the sealed pouch 300. The sealed pouch 300 preventsbacteria from entering the device 201 and infecting the eye. Aqueoushumor exiting the device 201 and entering the sealed pouch 300 creates avery shallow bleb. The bleb fluid may filter through the conjunctiva 30(FIG. 1) into the tears or evaporate therefrom, and the fluid may beabsorbed through the lymphatic system and capillaries thatinterpenetrate the conjunctiva 30 (FIG. 1). A fraction of the aqueoushumor contained in the bleb may potentially seep through the permeablesclera 26 and be absorbed by the choroidal capillaries.

The aqueous humor drainage device 201 can be implanted into the positionshown in FIG. 15 utilizing the following method. The pouch 300 is madeby dissecting the conjunctiva 30 at the limbus 32 in an incision areathat is less than one quadrant using miniature scissors (Vannas scissorsor similar) and dissecting and separating Tenon's membrane 36 from thesclera 26 over a few millimeters (a fornix-based flap). Then, holdingthe edge of the pouch 300 at its center with toothed forceps, the closedtips of a pair of blunt scissors (e.g. Westcott or similar) are slowlypushed downward toward the eye equator and opened up to separate(delaminate) Tenon's membrane 36 from the sclera 26. The scissors areagain closed; its tips pushed further forward and reopened to separate alarger area of Tenon's membrane 36. The process is repeated until thetips of the scissors are 17 to 20 mm away from the limbus 32. The pouch300 thusly created is larger at the equatorial base than at the limbalentry.

The pouch 300 is formed adjacent to the limbus 32. A mark, centered inthe middle of the conjunctival opening is made 2-3 mm behind the limbus'edge using a blunt caliper. A tissue ink can be used on the tip of thecaliper to increase contrast of the tissue mark. A hand-held instrument101 with a needle body 103 (FIG. 1) is prepared and the tip of theneedle body 103 is positioned at the mark made on the sclera. A surgicalpassage is fashioned to connect the scleral outer wall to the anteriorchamber by pushing the needle body 103 in a plane such that the tip ofthe needle body 103 enters the eye through the angle 28 into theanterior chamber 20. In this manner, the surgical passage passes throughthe conjuctiva-sclera in the vicinity of the angle 28 and into theanterior chamber 20. The instrument 101 may be a syringe that holds apharmacological solution, such as epinephrine or lidocain. The surgeonmay elect to dispense the solution from the syringe into the anteriorchamber 20 after introduction of the distal end of the syringe needlebody 103 into the anterior chamber 20. After waiting for some time(e.g., a few seconds), the needle body 103 is slowly retracted. Theaqueous humor drainage device 201 is inserted into the surgical passageinto the position shown in FIG. 15 whereby the distal end 209 exits intothe anterior chamber 20 of the eye and the tabs 213A, 213B arepositioned within the surgical passage. Before introducing the device201 into the surgical passage, the proximal end of the surgical passagecan be enlarged at the scleral surface by means of a stab incision witha sharp knife (such as the knife of FIGS. 18A and 18B as describedbelow) or by cutting the entrance to the sclera with the sharp edge ofthe needle body 103 as it is withdrawn. This stab incision can assist inthe introduction of the tabs 213A, 213B of the device 201 into thesurgical passage. Alternatively, prior to making the surgical passage,the sharp knife is used to make a shallow slit or stab-wound into thesclera. A needle is then inserted into the slit and the surgical passageformed under the limbus. The tabs 213A, 213B are then tucked into thestab wound as described above. The dimensions of the tabs 213A, 213Bcause the surrounding ocular tissue of the surgical passage to directlycontact the tabs 213A, 213B in order to form a seal between thesurrounding ocular tissue and the tabs 213A, 213B. The seal surroundsthe entire circumferential perimeter of the device defined by the tabs213A, 213B and prevents leakage of aqueous humor through the spacebetween the tube 203 and the surrounding ocular tissue of the surgicalpassage. The proximal end 207 of the tube 203 is positioned in the pouch300 as shown in FIG. 15. The aqueous humor drainage device 201 can bedeployed from an inserter device similar to that described in U.S. Pat.Nos. 7,431,709, 7,594,899, and 7,837,644 with one or two slots thataccommodate the tabs 213A, 213B of the device 201. Alternatively, theaqueous humor drainage device 201 can be inserted into the passage usinga stylet 301 and/or a trocar device 350 (or 410) as described below. Thepouch 300 is then closed with sutures 304. Instead of sutures, bipolardiathermy coagulation, laser welding or adhesives, such ascyanoacrylate, fibrin glue, etc. can be used to close the pouch 300.Further, a trocar can be used to facilitate placement of the aqueoushumor drainage device through the needle passage.

To minimize inflammation as well as reduce surgical time, the pouch 300can also be created by dissection of the conjunctiva at the limbus and,starting at one edge of the dissection, cutting the conjuctival tissueposteriorly for about 3 mm, thus creating a flap door. After forming thesurgical passage into the exposed sclera and through to the anteriorchamber, the device 201 is positioned in the surgical passage with theproximal end of the device in the pouch 300 as shown in FIG. 12. Thefreed edge of the conjunctiva 30 is then juxtaposed about 2 mm past itsoriginal position and held taut with a single suture, or a single laserweld, or a single-point bipolar diathermy coagulation, or with a singledot of adhesive. The edge of the conjunctiva 30 along the limbus 32 isnever treated, but left intact to prevent tissue necrosis that engendersfibrosis. The cornea-limbal epithelium cells will rapidly recover thewound edge (1 hour or less), sealing the conjunctival limbus.

A sponge, blotting paper or other suitable carrier loaded with one ormore therapeutic agents can be placed within the pouch 300 before it isclosed. Such therapeutic agent(s) release over time and minimizesfibrosis of Tenon's membrane to the sclera, thereby preventingre-lamination and closure of the bleb space (the interior space of theclosed pouch 300 that surrounds the proximal end 207 of the tube 203).The therapeutic agents(s) can include cytostatic agents (i.e.,anti-proliferation agents that prevent or delay cell division, forexample, by inhibiting replication of DNA, and/or by inhibiting spindlefiber formation, and/or by inhibiting cell migration) or other agentsthat minimize fibrosis or blood clots. Examples of such therapeuticagents are described below.

FIG. 16 shows the aqueous humor drainage device 201 with a stylet 301that is removably inserted into the lumen 205 of the proximal portion209 of the device 201 to aid in the insertion of the device 201 into theneedle-formed passage. The proximal end of the stylet 301 is bent in apig-tail configuration 302 to enable the surgeon to grip the stylet 301and remove it from the lumen 205 of the aqueous humor drainage device201 once it is in place. FIG. 17 shows another embodiment of the stylet301 where a larger tube 303 is crimped onto the proximal end of thestylet to facilitate gripping and removal.

FIGS. 18A and 18B show a hand-held knife 340 that can be used to makethe stab wound in the sclera to further secure the elements of theaqueous humor drainage device 201 in the sclera. The Diameter “a” of theknife edge 341 is less than the maximal cross-sectional diameter of thetabs 213A, 213B of the device 201 in order to enable a snug fit of thetabs 213A, 213B into the stab wound. The length b of the knife edge 341can be approximately the same dimension as the dimension a.

FIG. 18C shows an embodiment of a hand-held instrument 342 that includesa distal needle body 343 extending from a flat blade portion withcutting surfaces 344A, 344B. The needle body 343 creates the passageleading through the sclera and the cutting surfaces 344A, 344B create awidened stab wound in the sclera in one motion of the surgeon's hand.

When the needle body is removed from the needle-formed passage, theneedle passage can at times become oval (or collagen fibers cross thepassage or there is a bend in the passage), which results in difficultyplacing the aqueous humor drainage device 201 through the passage. Inorder to facilitate placement of the aqueous humor drainage device 201into the needle-formed passage through the sclera, a trocar 350 whichincludes a conduit 352 with a skived slot 351 (FIG. 19) can be provided.The conduit 352 is sized to receive the needle body 103 as well as thetube 203 of the aqueous humor drainage device 201. The trocar 350 isplaced over the needle body 103 to provide the assembly 360 shown inFIG. 20A. FIGS. 20B to 20E illustrate the function of the trocar 350.The assembly 360 is inserted into the needle-formed passage through thesclera 400 as is shown in FIG. 20B. The needle body 103 is then removedfrom the assembly leaving trocar 350 in place as shown in FIG. 20C. Theaqueous humor drainage device 201 is then fed through the trocar 350 asshown in FIG. 20D. The trocar 350 is then removed leaving the aqueoushumor drainage device 201 behind inside the needle-formed passage asshown in FIG. 20E. The elastic nature of the tube 203 of the device 201allows the tube 203 to bend and deform such that it passes through theslot 351 of the trocar 350 as the trocar 305 is removed. The position ofthe aqueous humor drainage device 201 within the passage can then beadjusted by the surgeon (for example, by further inserting the device201 into the passage) such that the tabs 213A, 213B interface to thetissue wall of the passage and provide a seal between the tissue and thedevice 201. In this position, the tabs 213A, 213B also act to fixate thedevice in the passage.

FIG. 21 shows another embodiment of a trocar 410, which includes aconduit 412 with a slot 411 which is skived partway along the conduit412. A section of the lid of the skived slot (e.g., tab 413) remainsintegral with the tube as is shown. The conduit 412 is sized to receivethe needle body 103 as well as the tube 203 of the aqueous humordrainage device 201. The trocar 410 is placed over the needle body 103with the hub 415 butting against the proximal end of conduit 412 toprovide the assembly shown in FIG. 22A. FIGS. 22B to 22D illustrate thefunction of the trocar 410. The assembly is inserted into theneedle-formed passage through the sclera 400 as is shown in FIG. 22B.The abutment of conduit 412 to the hub 415 prevents the trocar 410 fromslipping backward on the needle body as it is inserted through tissue.The needle body 103 is removed from trocar 410 as shown in FIG. 22C,which is facilitated by gripping tab 413 with a forceps as needle 103 ispulled out of trocar 410. Once the needle body 102 is removed, thetrocar 410 is cut at line 420 (for example, with scissors) and theproximal portion of the conduit 412 with tab 413 is discarded as shownin FIG. 22D. The aqueous humor drainage device 201 is then fed throughthe remaining trocar portion 421 into the needle-formed passage in amanner similar to the method described above in conjunction with FIG.20D. The trocar portion 421 is then removed leaving the aqueous humordrainage device 201 behind inside the needle-formed passage as shown inFIG. 20E. The elastic nature of the tube 203 of the device 201 allowsthe tube 203 to bend and deform such that it passes through the slot 411of the trocar portion 421 as the trocar portion 421 is removed. Theposition of the aqueous humor drainage device 201 within the passage canthen adjusted by the surgeon (for example, by further inserting thedevice 201 into the passage) such that the tabs 213A, 213B interface tothe tissue wall of the passage and provide a seal between the tissue andthe device 201. In this position, the tabs 213A, 213B also act to fixatethe device in the passage.

Another embodiment contemplated by this invention is to first form theneedle tract under the limbus with needle 103, then pre-load tube 203 ofthe aqueous humor drainage device 201 into trocar 350 or 410 and thenpush the assembly through the needle tract. The trocar is then removedfrom the needle tract as explained above.

The trocars of FIGS. 19 and 21 can be made from a stiff thin materialpreferably polyimide. Other materials that may function in this capacityare PEEK, PEEKEK, polyurethane, polypropylene, high molecular weightpolyethylene, Nylon, fluoropolymers, etc. Alternatively, the materialforming the trocars can be made from metal (preferably well-known metalsused in medical devices such as stainless steel, titanium, Nitinol,etc.). The main requirement is that when the trocar is inserted throughtissue that it not buckle. The wall thickness of the trocar should bebetween 0.0002″ and 0.003″; preferably between 0.001 and 0.003″. Theinner diameter of the trocar should be equal to or larger than thediameter of the needle body 103; that is, if inserted over a needle, orequal to or larger than the flexible tube 102 if the trocar ispre-loaded with the aqueous drainage device.

The polymeric aqueous humor drainage device 201 (or parts thereof) canbe loaded with one or more therapeutic agents that release over time andminimize fibrosis of the Tenon's membrane to the sclera, therebypreventing re-lamination and closing of the bleb space. The therapeuticagents(s) loaded into the device 100 can include cytostatic agents(i.e., anti-proliferation agents that prevent or delay cell division,for example, by inhibiting replication of DNA, and/or by inhibitingspindle fiber formation, and/or by inhibiting cell migration) or otheragents that minimize fibrosis or blood clots. Examples of suchtherapeutic agents follow.

Representative examples of therapeutic agents include the following:Visudyne, Lucentis (rhuFab V2 AMD), Combretastatin A4 Prodrug, SnET2,H8, VEGF Trap, Candy, LS 11 (Taporfin Sodium), AdPEDF, RetinoStat,Integrin, Panzem, Retaane, Anecortave Acetate, VEGFR-1 mRNA, ARGENTcell-signaling technology, Angiotensin II Inhibitor, Accutane forBlindness, Macugen (PEGylated aptamer), PTAMD, Optrin, AK-1003, NX 1838,Antagonists of avb3 and 5, Neovastat, Eos 200-F and any other VEGFinhibitor.

Other therapeutic agents can be used such as: mitomycin C,5-fluorouracil, corticosteroids (corticosteroid triamcinolone acetonideis most common), modified toxins, methotrexate, adriamycin,radionuclides (e.g., such as disclosed in U.S. Pat. No. 4,897,255,herein incorporated by reference in it entirety), protein kinaseinhibitors (including staurosporin, which is a protein kinase Cinhibitor, as well as a diindoloalkaloids and stimulators of theproduction or activation of TGF-beta, including tamoxifen andderivatives of functional equivalents, e.g., plasmin, heparin, compoundscapable of reducing the level or inactivating the lipoprotein Lp(a) orthe glycoprotein apolipoprotein(a) thereof), nitric oxide releasingcompounds (e.g., nitroglycerin) or analogs or functional equivalentsthereof, paclitaxel or analogs or functional equivalents thereof (e.g.,taxotere or an agent based on Taxol®, whose active ingredient ispaclitaxel), inhibitors of specific enzymes (such as the nuclear enzymeDNA topoisomerase II and DAN polymerase, RNA polyermase, adenl guanylcyclase), superoxide dismutase inhibitors, terminaldeoxynucleotidyl-transferas, reverse transcriptase, antisenseoligonucleotides that suppress cell proliferation, angiogenesisinhibitors (e.g., endostatin, angiostatin and squalamine), rapamycin,everolimus, zotarolimus, cerivastatin, and flavopiridol and suramin andthe like.

Other examples of therapeutic agents include the following: peptidic ormimetic inhibitors, such as antagonists, agonists, or competitive ornon-competitive inhibitors of cellular factors that may triggerproliferation of cells or pericytes (e.g., cytokines (for example,interleukins such as IL-1), growth factors (for example, PDGF, TGF-alphaor -beta, tumor necrosis factor, smooth muscle- and endothelial-derivedgrowth factors such as endothelin or FGF), homing receptors (forexample, for platelets or leukocytes), and extracellular matrixreceptors (for example, integrins).

Representative examples of useful therapeutic agents in the category ofagents that address cell proliferation include: subfragments of heparin,triazolopyrimidine (for example, trapidil, which is a PDGF antagonist),lovastatin; and prostaglandins E1 or I2.

Several of the above and numerous additional therapeutic agentsappropriate for the practice of the present invention are disclosed inU.S. Pat. Nos. 5,733,925 and 6,545,097, both of which are hereinincorporated by reference in their entirety.

If desired, a therapeutic agent of interest can be provided at the sametime as the polymer from which the device 201 is realized, for example,by adding it to a polymer melt during thermoplastic processing or byadding it to a polymer solution during solvent-based processing.Alternatively, a therapeutic agent can be provided after formation ofthe device or device portion. As an example of these embodiments, thetherapeutic agent can be dissolved in a solvent that is compatible withboth the device polymer and the therapeutic agent. Preferably, thedevice polymer is at most only slightly soluble in this solvent.Subsequently, the solution is contacted with the device or deviceportion such that the therapeutic agent is loaded (e.g., byleaching/diffusion) into the copolymer. For this purpose, the device ordevice portion can be immersed or dipped into the solution, the solutioncan be applied to the device or component, for example, by spraying,printing dip coating, immersing in a fluidized bed and so forth. Thedevice or component can subsequently be dried, with the therapeuticagent remaining therein.

In another alternative, the therapeutic agent may be provided within amatrix comprising the polymer of the device 201. The therapeutic agentcan also be covalently bonded, hydrogen bonded, or electrostaticallybound to the polymer of the device 201. As specific examples, nitricoxide releasing functional groups such as S-nitroso-thiols can beprovided in connection with the polymer, or the polymer can be providedwith charged functional groups to attach therapeutic groups withoppositely charged functionalities.

In yet another alternative embodiment, the therapeutic agent can beprecipitated onto one or more surfaces of the device 201 (or deviceportion). These one or more surface(s) can be subsequently covered witha coating of polymer (with or without additional therapeutic agent) asdescribed above.

Hence, for purposes herein, when it is stated herein that the polymer is“loaded” with therapeutic agent, it is meant that the therapeutic agentis associated with the polymer in a fashion like those discussed aboveor in a related fashion.

In some instances a binder may be useful for adhesion to a substrate.Examples of materials appropriate for binders in connection with thepresent invention include silanes, titanates, isocyanates, carboxyls,amides, amines, acrylates hydroxyls, and epoxides, including specificpolymers such as EVA, polyisobutylene, natural rubbers, polyurethanes,siloxane coupling agents, ethylene and propylene oxides.

It also may be useful to coat the polymer of the device 201 (which mayor may not contain a therapeutic agent) with an additional polymer layer(which may or may not contain a therapeutic agent). This layer mayserve, for example, as a boundary layer to retard diffusion of thetherapeutic agent and prevent a burst phenomenon whereby much of theagent is released immediately upon exposure of the device or deviceportion to the implant site. The material constituting the coating, orboundary layer, may or may not be the same polymer as the loadedpolymer. For example, the barrier layer may also be a polymer or smallmolecule from the following classes: polycarboxylic acids, includingpolyacrylic acid; cellulosic polymers, including cellulose acetate andcellulose nitrate; gelatin; polyvinylpyrrolidone; cross-linkedpolyvinylpyrrolidone; polyanhydrides including maleic anhydridepolymers; polyamides; polyvinyl alcohols; copolymers of vinyl monomerssuch as EVA (ethylene-vinyl acetate copolymer); polyvinyl ethers;polyvinyl aromatics; polyethylene oxides; glycosaminoglycans;polysaccharides; polyesters including polyethylene terephthalate;polyacrylamides; polyethers; polyether sulfone; polycarbonate;polyalkylenes including polypropylene, polyethylene and high molecularweight polyethylene; halogenated polyalkylenes includingpolytetrafluoroethylene; polyurethanes; polyorthoesters; polypeptides,including proteins; silicones; siloxane polymers; polylactic acid;polyglycolic acid; polycaprolactone; polyhydroxybutyrate valerate andblends and copolymers thereof; coatings from polymer dispersions such aspolyurethane dispersions (BAYHDROL®, etc.); fibrin; collagen andderivatives thereof; polysaccharides such as celluloses, starches,dextrans, alginates and derivatives; and hyaluronic acid.

Copolymers and mixtures of the above are also contemplated.

It is also possible to form the aqueous humor drainage device 201 (ordevice portion) with blends by adding one or more of the above or otherpolymers to a block copolymer. Examples include the following:

-   -   Blends can be formed with homopolymers that are miscible with        one of the block copolymer phases. For example, polyphenylene        oxide is miscible with the styrene blocks of        polystyrene-polyisobutylene-polystyrene copolymer. This should        increase the strength of a molded part or coating made from        polystyrene-polyisobutylene-polystyrene copolymer and        polyphenylene oxide.    -   Blends can be made with added polymers or other copolymers that        are not completely miscible with the blocks of the block        copolymer. The added polymer or copolymer may be advantageous,        for example, in that it is compatible with another therapeutic        agent, or it may alter the release rate of the therapeutic agent        from the block copolymer (e.g.,        polystyrene-polyisobutylene-polystyrene copolymer).    -   Blends can be made with a component such as sugar (see list        above) that can be leached from the device 201 (or device        portion), rendering the device or device component more porous        and controlling the release rate through the porous structure.

The release rate of therapeutic agent from the therapeutic-agent-loadedpolymers of the present invention can be varied in a number of ways.Examples include:

-   -   Varying the molecular weight of the block copolymers.    -   Varying the specific constituents selected for the elastomeric        and thermoplastic portions of the block copolymers and the        relative amounts of these constituents.    -   Varying the type and relative amounts of solvents used in        processing the block copolymers.    -   Varying the porosity of the block copolymers.    -   Providing a boundary layer over the block copolymer.    -   Blending the block copolymer with other polymers or copolymers.

Moreover, although it is seemingly desirable to provide control over therelease of the therapeutic agent (e.g., as a fast release (hours) or asa slow release (weeks)), it may not be necessary to control the releaseof the therapeutic agent. In such embodiments, one or more of thetherapeutic drug agents described herein (e.g., an antiproliferativeagent derived from mitomycin C or 5-fluorouracil) may be injected intothe pouch 300 at the time of surgery.

There have been described and illustrated herein several embodiments ofglaucoma implant devices, kits and methods that divert aqueous humorfrom the anterior chamber of the eye and surgical methods associatedtherewith. While particular embodiments of the invention have beendescribed, it is not intended that the invention be limited thereto, asit is intended that the invention be as broad in scope as the art willallow and that the specification be read likewise.

Thus, while particular methods of manufacture have been disclosed, itwill be understood that other manufacture methods can be used. Forexample, because the copolymer materials described herein have athermoplastic character, a variety of standard thermoplastic processingtechniques can be used to for the devices described herein. Suchtechniques include compression molding, injection molding, blow molding,spinning, vacuum forming and calendaring, and extrusion into tubes andthe like. Such devices can also be made using solvent-based techniquesinvolving solvent casting, spin coating, solvent spraying, dipping,fiber forming, ink jet techniques and the like. Also, while it ispreferred that the aqueous humor drainage device be realized by a simpletubular structure, it will be recognized that adaptations may be made ofsuch structures. For example, other duct forming structures and shapescan be used. In another example, the device may include holes throughthe side wall of the tubular structure. In another example, the tubularstructure may include multiple lumens therein. Also, while it ispreferred that the aqueous humor drainage device be realized by simpleplanar tab structures, it will be recognized that adaptations may bemade of such structures. It will therefore be appreciated by thoseskilled in the art that yet other modifications could be made to theprovided invention without deviating from its spirit and scope asclaimed.

What is claimed is:
 1. An aqueous humor drainage device for implantationinto a tissue passage leading into the anterior chamber of the eye, thedevice comprising: a flexible tube and a tissue sealing structureextending radially outward from said tube in at least two differentdirections; wherein said tube defines a duct for diverting aqueous humorfrom the anterior chamber, said tube having a central axis and having aproximal portion defining a cylindrical outer surface and a distalportion defining a cylindrical outer surface, the cylindrical outersurfaces of the proximal portion and the distal portion having a firstmaximal cross-sectional dimension; and wherein said tissue sealingstructure is spaced apart from and intermediate the cylindrical outersurfaces of said proximal and distal portions of said tube, said tissuesealing structure extending radially outward beyond the cylindricalouter surfaces of said proximal and distal portions of said tube, andsaid tissue sealing structure having a second maximal cross-sectionaldimension that is greater than said first maximal cross-sectionaldimension and configured to interface to the tissue passage and form aseal between the tissue passage and said tissue sealing structure. 2.The aqueous humor drainage device according to claim 1, wherein saiddevice consists essentially of said flexible tube and said tissuesealing structure.
 3. The aqueous humor drainage device according toclaim 1, wherein the second maximal cross-sectional dimension of saidtissue sealing structure is defined by at least one surface or portionthereof that is spaced from the cylindrical outer surfaces of theproximal portion and the distal portion of the tube and that interfacesto the tissue passage in order to form the seal between the tissuepassage and said tissue sealing structure.
 4. The aqueous humor drainagedevice according to claim 1, wherein said tissue sealing structure has aproximal surface and a distal surface, said distal surface having atapered profile that extends away from the distal portion of said tubetoward the proximal portion of said tube.
 5. The aqueous humor drainagedevice according to claim 1, wherein said tissue sealing structure has aproximal surface and a distal surface, said distal surface having atapered profile that faces the distal end of said tube.
 6. The aqueoushumor drainage device according to claim 1, wherein said second maximalcross-sectional dimension of said tissue sealing structure is defined byat least one blunt surface formed between proximal and distal surfacesof said tissue sealing structure.
 7. The aqueous humor drainage deviceaccording to claim 1, wherein said tissue sealing structure isdimensioned to fit entirely within the tissue passage.
 8. The aqueoushumor drainage device according to claim 1, wherein said differentdirections extend opposite one another transverse to the central axis ofthe tube.
 9. The aqueous humor drainage device according to claim 1,wherein: said tissue sealing structure has a circular cross-section in adirection transverse to the central axis of the tube; and/or said tissuesealing structure has a rhomboid cross-section in a direction transverseto the central axis of the tube; and/or said tissue sealing structurehas an oblong cross-section in a direction transverse to the centralaxis of the tube; and/or said tissue sealing structure hassemi-elliptical ends; and/or said tissue sealing structure has an ovoidcross-section in a direction transverse to the central axis of the tube;and/or the second maximal cross-sectional dimension of said tissuesealing structure lies along a first direction transverse to the centralaxis of the tube, and said tissue sealing structure has a third maximalcross-sectional dimension that lies along a second direction transverseto the central axis of the tube and orthogonal to the first direction,wherein the third maximal cross-sectional dimension is less than thesecond maximal cross-sectional dimension.
 10. The aqueous humor drainagedevice according to claim 1, wherein said tissue sealing structure has ablunt outer surface with only rounded features.
 11. The aqueous humordrainage device according to claim 1, wherein said first maximalcross-sectional dimension is no more than 0.4 mm, and said secondmaximal cross-sectional dimension is at least 0.9 mm.
 12. The aqueoushumor drainage device according to claim 1, wherein said tube isrealized from a homogenous polymeric material selected from the groupconsisting of SIBS material, silicone rubber, a polyolefin polymer, apolyurethane polymer, an acrylic polymer, a fluoropolymer, a polyamidepolymer, a hydrogel polymer, a biological based structure, a softpolymer foam material, a porous polymer material, and combinationsthereof.
 13. An aqueous humor drainage device for implantation into atissue passage leading into the anterior chamber of the eye, the deviceconsisting essentially of a flexible tube and first and second tabs;wherein said tube defines a duct for diverting aqueous humor from theanterior chamber, said tube having a proximal portion defining acylindrical outer surface and a distal portion defining a cylindricalouter surface, the cylindrical outer surfaces of the proximal portionand the distal portion having a first maximal cross-sectional dimension;and wherein said first and second tabs are spaced apart from andintermediate the cylindrical outer surfaces of said proximal and distalportions of said tube, said first and second tabs extending in a commonplane radially outward beyond the cylindrical outer surfaces of saidproximal and distal portions of said tube with a proximal surface and adistal surface, said distal surface having a tapered profile thatextends away from the distal portion of said tube toward the proximalportion of said tube, said first and second tabs having a second maximalcross-sectional dimension that is greater than said first maximalcross-sectional dimension and configured to form a seal between thetissue passage and said first and second tabs, and said second maximalcross-sectional dimension of said first and second tabs defined by atleast one blunt surface.
 14. The aqueous humor drainage device accordingto claim 13, wherein said first and second tabs are mirror images of oneanother reflected about the central axis of said tube.
 15. The aqueoushumor drainage device according to claim 13, wherein said first andsecond tabs are generally planar and extend transverse to the centralaxis of the tube.
 16. The aqueous humor drainage device according toclaim 15, wherein said first and second tabs have a maximal thickness nomore than the first maximal cross-sectional diameter of the tube. 17.The aqueous humor drainage device according to claim 15, wherein saidfirst and second tabs decrease in thickness as they radially extend fromthe central axis of the tube.
 18. The aqueous humor drainage deviceaccording to claim 13, wherein said first and second tabs have roundedsurfaces within the common plane.
 19. The aqueous humor drainage deviceaccording to claim 13, wherein said first and second tabs aredimensioned to fit entirely within the tissue passage.
 20. The aqueoushumor drainage device according to claim 13, wherein said first andsecond tabs each have a distal surface having a tapered profile facingthe distal end of said tube.
 21. The aqueous humor drainage deviceaccording to claim 13, wherein said first and second tabs have ahardness different from said tube.
 22. The aqueous humor drainage deviceaccording to claim 13, wherein said first and second tabs are configuredto deform in response to forces applied by surrounding ocular tissue.23. The aqueous humor drainage device according to claim 13, whereinsaid first and second tabs each have a hardness within a range betweenShore 30A and Shore 80A.